Outlet Testing Devices: 4 Picks Compared
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An outlet testing device is a plug-in or pen-style tool that reads the wiring of a standard US receptacle, or detects voltage near it without touching the wires. The four listings here cover three kinds: a GFCI outlet tester with indicator lights, a combined kit with a non-contact voltage pen, and a circuit breaker finder that also includes a GFCI test. Figures come from the listing text, with the check date of 18 October 2026. The research set for this keyword held no plug-in outlet testers, so every pick comes from the extra product files.
Quick answer
For a plug-in check of wiring and GFCI function, the Goldeep ST20 lists the widest set of wiring faults and an LCD. For a kit that also detects voltage near a wire, the focemta FTVT01 pairs a non-contact voltage pen with a GFCI tester. For a breaker search, the NOYAFA NF-8401 is the only listing here that is primarily a circuit breaker finder. The KLASLAV outlet tester is the simplest of the four and lists a voltage input of 110 V to 125 V.
The four picks at a glance
| Device (ASIN) | Type | Listed AC input | Display or indicator |
|---|---|---|---|
| Goldeep GFCI Outlet Tester ST20 (B0H1PVNPMY) | Plug-in GFCI and wiring tester | Minimum 120 V | Color LCD and bottom indicators |
| focemta Non-Contact Voltage Tester and Outlet Tester FTVT01 (B0H9RJ8DF2) | Pen plus plug-in GFCI tester | Pen 12 V to 1000 V; GFCI 90 V to 135 V | Pen color display; outlet tester uses lights only |
| NOYAFA Circuit Breaker Finder NF-8401 (B0H49BW714) | Breaker finder with GFCI test | 90 V to 120 V | Flashing light and beeps |
| KLASLAV Outlet Tester with Test Pen (B0H2XNYQYK) | Plug-in wiring tester and test pen | 110 V to 125 V | Indicator lights |
How these four were chosen
We kept listings whose title names an outlet tester, GFCI outlet tester or circuit breaker finder that includes an outlet check, and whose text gives an AC voltage input or a wiring check. The research set held 12 listings, and none of them is a plug-in outlet tester. The product files added four extra listings for this keyword, and all four are included here. The listings are dated 18 October 2026.
1. Goldeep GFCI Outlet Tester ST20
The listing describes a plug-in tester for North American three-wire 120 V outlets. It shows a color LCD and bottom indicators, green for a correct outlet and red for a fault. The bullets list open hot, open neutral, open ground, hot and ground reversed, and other wiring faults. The specification field gives a minimum operating voltage of 120 V. The auto-hold function locks the reading when the tester is removed. The GFCI function, according to the bullets, needs a circuit with correct wiring and a breaker in place, and a short press of the TEST key sends a leakage current of 6 mA to 9 mA to the ground wire. The tester shuts off after about 3 minutes if it is not used. The listed operating temperature is 32 °F to 122 °F.
Check the Goldeep GFCI outlet tester on Amazon
2. focemta Non-Contact Voltage Tester and Outlet Tester FTVT01
The listing describes a two-in-one kit: a dual-range non-contact voltage pen and a GFCI outlet tester. The pen has two selectable ranges, 12 V to 1000 V AC and 48 V to 1000 V AC, with NCV detection, a color display and an LED flashlight. The GFCI tester is listed for 90 V to 135 V AC, and it shows wiring status through indicator lights with no screen. The bullets say the GFCI test checks whether GFCI receptacles trip. The specification field gives CE CAT III 1000 V and CAT IV 600 V. The box includes one pen, one outlet tester, two AAA batteries and a manual. The title says “Color Screen Display”, but the bullets place the screen on the pen only, so the outlet tester has no screen.
Check the focemta voltage tester and outlet tester on Amazon
3. NOYAFA Circuit Breaker Finder NF-8401
The listing states that this kit finds the correct breaker on energized 90 V to 120 V AC circuits. The transmitter connects to an outlet or fixture, and the receiver scans the panel. The receiver gives a flashing light and an audible beep when it finds the right breaker, and it has adjustable sensitivity. The bullets also list a built-in GFCI outlet test and non-contact voltage detection. The kit includes an LED flashlight, a low-battery indicator, auto shut-off and an adapter. The specification field lists a minimum of 90 V AC and a maximum of 120 V AC, with a count of five items. The listing describes the device as suitable for residential, commercial and maintenance work.
Check the NOYAFA circuit breaker finder on Amazon
4. KLASLAV Outlet Tester with Test Pen
The listing describes a white plug-in outlet tester for North American outlets that identifies wiring faults and detects grounding. The package includes one outlet tester and one test pen. The specification fields give a minimum operating voltage of 110 V, a maximum of 125 V and a maximum AC current of 15 A. The tester is made of ABS plastic and measures about 3.5 by 1.5 by 1 inches, and it weighs 2 ounces. The listed operating temperature is 32 °F to 104 °F. The title refers to grounding products, but the compatible-devices field names grounded electrical receptacles, so the listing’s use is the outlet, not an earthing mat.
Check the KLASLAV outlet tester on Amazon
Worked example: a 115 V outlet and a 120 V outlet
Take a 115 V outlet first. The Goldeep listing gives 120 V as its minimum operating voltage, so 115 V is below its listed input. The KLASLAV listing gives 110 V as its minimum, so 115 V is inside its band. The NOYAFA listing’s 90 V to 120 V band and the focemta GFCI tester’s 90 V to 135 V band both include 115 V. The listings do not say what the Goldeep tester shows below its minimum, so do not read a result from it at 115 V.
Now take a 120 V outlet. All four listings include 120 V in their bands, although the Goldeep figure is its minimum exactly. The focemta GFCI band runs from 90 V to 135 V, so 120 V sits 15 V below its top. The NOYAFA band ends at 120 V, so 120 V is at the top of its range. The GFCI test on the Goldeep tester needs a 6 mA to 9 mA leakage current, a figure that the listing gives but does not explain.
What the listings do not say
None of the four listings gives an accuracy figure for its outlet or voltage reading, and none gives an IP rating. The Goldeep and KLASLAV listings give temperature ranges but no humidity figure. The focemta title says color screen display, but the bullets put the screen on the pen only, and the NOYAFA listing does not state how its GFCI test is run. The KLASLAV listing’s title refers to grounding products while its bullets refer to outlets, and the listing does not explain the difference. None of the four lists a safety standard for the outlet tester on its own.
Frequently asked questions
Which outlet tester shows the most wiring faults?
The Goldeep ST20 lists open hot, open neutral, open ground, hot and ground reversed, and other wiring faults in its bullets. The KLASLAV listing names identification of wiring faults in general terms, and the focemta outlet tester shows wiring status through indicator lights.
Can these testers check for a GFCI?
The Goldeep ST20 describes a GFCI function with a TEST key, and the focemta GFCI tester says it checks whether GFCI receptacles trip. The NOYAFA breaker finder includes a built-in GFCI outlet test. The KLASLAV listing does not describe a GFCI function.
Does the NOYAFA kit work with the breaker panel?
Yes. The listing describes a transmitter that connects to an outlet or fixture and a receiver that scans the panel for the correct breaker, with a flash and beep when it finds it. Its range is 90 V to 120 V AC.
Do any of these show a voltage reading?
None of the four listings describes a numeric voltage display. The focemta pen has a color display, but the listing does not describe it showing a numeric voltage. The four listings rely on lights, beeps or indicators.
Conclusion
For a plug-in wiring and GFCI check with a stated fault list, the Goldeep ST20 has the clearest listing data. The focemta kit is the best fit if you also want a non-contact voltage pen, with a GFCI tester that has no screen. The NOYAFA breaker finder suits a search for the right breaker, and the KLASLAV tester is a simple option for an outlet check. Confirm the voltage input and the kit contents on the live listing before you buy.
For related reading, see outlet checker, best receptacle tester, best plug tester and best breaker tester.
